ux164 (ruffian) fixes

ux164 (ruffian) fixes

[Ivan Kokshaysky]

Two issues preventing ruffians from booting 2.4 (with bridges patch)
were found and fixed.
 - rather trivial one: someone decided that interrupt 4
   (irq 20 from builtin scsi) is 'bogus' ;-)
 - another issue is way not trivial and cost Michal and me a
   lot of sweat. Type 1 PCI configuration space accesses (and to
   some degree type 0 accesses to the bridge itself) were subtly
   broken. In other words, these accesses were failing randomly
   causing all sorts of havoc. At some point I managed to break
   them completely just by adding one extra mb()...
   Copying the code from 2.2 solved the problem - but it's a kind
   of magic.
   Interesting, other pyxis machines do not seem to be so sensitive,
   so I guess some design problems with ux164 motherboard - all this
   looks pretty much like timing issues.

Many thanks to Michal for that painful and time consuming testing
he has done.

Ivan.

--- 2.4.0t11/arch/alpha/kernel/core_cia.c	Fri Oct 27 21:55:01 2000
+++ linux/arch/alpha/kernel/core_cia.c	Thu Nov 16 17:46:54 2000
@@ -119,6 +119,7 @@ conf_read(unsigned long addr, unsigned c
 	stat0 = *(vip)CIA_IOC_CIA_ERR;
 	*(vip)CIA_IOC_CIA_ERR = stat0;
 	mb();
+	*(vip)CIA_IOC_CIA_ERR; /* re-read to force write */
 
 	/* If Type1 access, must set CIA CFG. */
 	if (type1) {
@@ -128,6 +129,7 @@ conf_read(unsigned long addr, unsigned c
 		*(vip)CIA_IOC_CFG;
 	}
 
+	mb();
 	draina();
 	mcheck_expected(0) = 1;
 	mcheck_taken(0) = 0;
@@ -171,6 +173,7 @@ conf_write(unsigned long addr, unsigned 
 	stat0 = *(vip)CIA_IOC_CIA_ERR;
 	*(vip)CIA_IOC_CIA_ERR = stat0;
 	mb();
+	*(vip)CIA_IOC_CIA_ERR; /* re-read to force write */
 
 	/* If Type1 access, must set CIA CFG.  */
 	if (type1) {
@@ -180,6 +183,7 @@ conf_write(unsigned long addr, unsigned 
 		*(vip)CIA_IOC_CFG;
 	}
 
+	mb();
 	draina();
 	mcheck_expected(0) = 1;
 	mcheck_taken(0) = 0;
@@ -188,7 +192,7 @@ conf_write(unsigned long addr, unsigned 
 	/* Access configuration space.  */
 	*(vip)addr = value;
 	mb();
-	mb();  /* magic */
+	*(vip)addr; /* read back to force the write */
 
 	mcheck_expected(0) = 0;
 	mb();
@@ -606,7 +610,8 @@ do_init_arch(int is_pyxis)
 	*(vip)CIA_IOC_ERR_MASK = temp;
 
 	/* Clear all currently pending errors.  */
-	*(vip)CIA_IOC_CIA_ERR = 0;
+	temp = *(vip)CIA_IOC_CIA_ERR;
+	*(vip)CIA_IOC_CIA_ERR = temp;
 
 	/* Turn on mchecks.  */
 	temp = *(vip)CIA_IOC_CIA_CTRL;
--- 2.4.0t11/arch/alpha/kernel/sys_ruffian.c	Sun Nov  5 16:16:43 2000
+++ linux/arch/alpha/kernel/sys_ruffian.c	Tue Nov 21 00:25:42 2000
@@ -56,9 +56,9 @@ ruffian_init_irq(void)
 	
 	init_i8259a_irqs();
 
-	/* Not interested in the bogus interrupts (0,3,4,6), 
+	/* Not interested in the bogus interrupts (0,3,6),
 	   NMI (1), HALT (2), flash (5), or 21142 (8).  */
-	init_pyxis_irqs(0x17f0000);
+	init_pyxis_irqs(0x16f0000);
 
 	common_init_isa_dma();
 }
-
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Re: ux164 (ruffian) fixes

[Richard Henderson]

On Tue, Nov 21, 2000 at 06:46:09PM +0300, Ivan Kokshaysky wrote:
>    Interesting, other pyxis machines do not seem to be so sensitive,
>    so I guess some design problems with ux164 motherboard - all this
>    looks pretty much like timing issues.

Wow.  Thanks for following through on this.


r~
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Re: ux164 (ruffian) fixes

[Michal Jaegermann]

On Tue, Nov 21, 2000 at 10:47:20AM -0800, Richard Henderson wrote:
> On Tue, Nov 21, 2000 at 06:46:09PM +0300, Ivan Kokshaysky wrote:
> >    Interesting, other pyxis machines do not seem to be so sensitive,
> >    so I guess some design problems with ux164 motherboard - all this
> >    looks pretty much like timing issues.
> 
> Wow.  Thanks for following through on this.

I can now confirm that I can boot using SCSI disks (the fact that
this was possible for a while into IDE was a life-saver here :-)
a Ruffian (pyxis) Alpha using 2.4.0-test11 kernel and two patches
posted by Ivan (bridges-2.4.0t11.gz and extra ruffian fixes).

Here are fragments from 'dmesg':

....
Booting on Ruffian using machine vector Ruffian from MILO
Command line: bootdevice=sda2 bootfile=/vml240o11.gz root=/dev/sda2
....
SCSI subsystem driver Revision: 1.00
sym53c8xx: at PCI bus 1, device 13, function 0
sym53c8xx: 53c875 detected 
sym53c875-0: rev 0x3 on pci bus 1 device 13 function 0 irq 20
sym53c875-0: ID 7, Fast-20, Parity Checking
sym53c875-0: on-chip RAM at 0xa101000
sym53c875-0: restart (scsi reset).
sym53c875-0: Downloading SCSI SCRIPTS.
scsi0 : sym53c8xx - version 1.6b
  Vendor: IBM       Model: DDRS-39130D       Rev: DC1B
  Type:   Direct-Access                      ANSI SCSI revision: 02
  Vendor: TOSHIBA   Model: CD-ROM XM-6201TA  Rev: 1037
  Type:   CD-ROM                             ANSI SCSI revision: 02
  Vendor: IBM       Model: DDRS-34560D       Rev: DC1B
  Type:   Direct-Access                      ANSI SCSI revision: 02
sym53c875-0-<2,0>: tagged command queue depth set to 8
sym53c875-0-<10,0>: tagged command queue depth set to 8
Detected scsi disk sda at scsi0, channel 0, id 2, lun 0
Detected scsi disk sdb at scsi0, channel 0, id 10, lun 0
....
VFS: Mounted root (ext2 filesystem) readonly.

Those who posted "me too" could you please test that this is not
only a fluke on my particular machine?

Thanks a bunch, Ivan. Also thanks are extended to Gerard Roudier who
provided a crucial hint in the moment when we appeared to be completly
stuck. :-)

  Michal

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